Firearm for low velocity projectiles

ABSTRACT

A firearm for low velocity projectiles has a barrel for launching the projectiles, and a fire control system. The fire control system comprises a sight having a longitudinal axis, sensors for sensing data of a target object, and first means for adjusting a line of sight of the sight relative to the longitudinal axis of the sight. The adjusting is effected by a predetermined angle as a function of the data. Further, second means are provided for adjusting the longitudinal axis of the sight relative to a bore axis of the barrel.

FIELD OF THE INVENTION

The invention, generally, is related to the field of firearms for low velocity projectiles, in particular grenade launchers and mortars.

More specifically, the invention is related to a firearm for low velocity projectiles having a barrel for launching the projectiles, and a fire control system, the fire control system comprising a sight having a longitudinal axis, sensors for sensing data of a target object, and first means for adjusting a line of sight of the sight relative to the longitudinal axis of the sight, the adjusting being effected by a predetermined angle as a function of the data.

BACKGROUND OF THE INVENTION

In the context of the present invention, the term “firearms for low velocity projectiles” is to be understood to comprise portable firearms with projectiles of about 30 to about 150 mm diameter. Such firearms are, for example, grenade weapons like grenade launchers or grenade accessories for portable firearms, all being carried by a gunner and being fired when the gunner is standing free or when he puts the firearm on a rest. However, the invention is also related to grenade weapons like grenade launchers standing on a stand, in particular a tripod, and are fired from said stand. Moreover, the invention is also related to weapons which launch uncontrolled, low velocity projectiles being partly or wholly propelled. Finally, the invention is related to weapons, irrespective of whether they are particularly designed for launching low velocity projectiles or may be enabled to do so by means of additional equipment.

A fire control system in the context of the present invention is to be understood to mean a system which may either comprise a fire control computer integrated into the firearm or comprises a separate computer that is carried by the gunner and, for example, may be configured as a functional unit connected to a central computer. The fire control system, further, comprises all necessary means for elevating the firearm. The fire control system may be integrated into the weapon or, as the case may be, may be configured as an adapter that may be mounted to the weapon.

The projectiles used in connection with such firearms have a muzzle velocity of typically between 50 and 200 m/s. These velocities are about one order of magnitude lower as compared to conventional muzzle velocities of firearms for high velocity projectiles, i.e. rifles (having a bore diameter of up to 13 mm) and of cannons (bore diameter above about 20 mm).

As compared to the distance of usual target objects, the projectiles fired from such firearms have a relatively flat trajectory due to the high velocity. Therefore, rifles normally do not require complicate fire control systems, notwithstanding special firearms for precision marksmen.

However, for firearms launching low velocity projectiles the circumstances are different because the projectiles have an essentially lower velocity and, hence, have a substantially curved and parabolic trajectory, also due to their higher air resistance. The probabilities to hit a target (so-called hit images) are, therefore, pretty bad in practice for such firearms, in particular when the target object is at a different height as compared to the gunner. Simple sights, for example so-called ladder sights, do not take such height differences into account. In such a situation, the gunner must rely on estimated values based on experience which, however, often do not result in firings hitting the target.

In order to improve the hit precision, mechanical aids have long been known. U.S. Pat. No. 3,568,324, for example, discloses a battle sight for an auxiliary projectile launcher. The sight essentially consists of a bar which may be swivelled into the line of sight of the gunner and which, then, extends under right angles relative to the barrel. The metal bar is provided with openings arranged at a distance from each other and through which the target object may be aimed at. Each of the openings is associated to a certain distance value. In such a way, a quadrant elevation for the barrel may be set, the elevation being set such that the launched grenade with its parabolic trajectory exactly hits the position of the target object. It goes without saying that this sight may only be of very course assistance because the aiming accuracy is only small and the association of the openings to a distance of the target object may, of course, only be exact for a certain type of projectile (velocity, shape, weight). An elevation of the line of sight remains out of consideration.

European patent specification EP 1 153 259 B1 and, also, British published patent application 2 068 091 A, and German patent publication document 19 46 972 B2 disclose electronic/optical aiming instruments for attacking tanks at low distance. In these instruments, the respective sight is provided with a range finder and a speed sensor which cooperate with an electronic evaluation unit. This unit, in turn, controls one of a plurality of leading marks as a function of signals from the range finder and from the speed sensor, respectively. In such a way, the weapon is directed such that the quadrant elevation, being essentially distance-depending, as well as a lead angle, being essentially speed-depending, are taken into account.

These prior art aiming instruments have the disadvantage that the line of sight may only be adjusted relative to the longitudinal axis of the sight within a relatively small range. For grenade weapons, this is often insufficient when these weapons are used at highly differing distances relative to the target object or with high differences in height between the gunner and the target object.

German patent publication document DE 19 46 972 C3, finally, discloses a sight, in particular a sighting telescope, for a firearm for high velocity projectiles, namely a rifle. This prior art sight comprises a motor for adjusting the angle between the sight and the bore axis of the rifle barrel as a function of the prevailing elevation angle of the bore axis. By doing so, a compensation for the deviation from the hit point shall be effected for a rifle which, in a horizontal direction, had been shot in for a predetermined distance of e.g. 150 m. In such a situation, the deviation from the hit point for the predetermined distance mentioned before, is about 92 cm, when the rifle is not fired in a horizontal direction but e.g. in a mountain terrain with an inclination of 75° relative to the horizontal direction.

This prior art apparatus is exclusively intended to be used for rifles, and, therefore, it has the disadvantage that it necessitates a mechanical adjustment, even for small attack angles. For large attack angles, as may occur for grenade launchers, this would result in unacceptable long adjustment times.

SUMMARY OF THE INVENTION

It is, therefore, an object underlying the invention to improve a firearm of the type specified at the outset, such that the above-mentioned disadvantages are avoided. In particular, a firearm for low velocity projectiles shall be made available which makes a high rate of hits possible, even when target objects shall be hit which are located at highly differing distances and/or heights and/or move at highly different speeds.

For a firearm of the type specified at the outset, this object is achieved by a firearm for low velocity projectiles having a barrel for launching the projectiles, and a fire control system, the fire control system comprising:

-   -   a sight having a longitudinal axis;     -   sensors for sensing data of a target object;     -   first means for adjusting a line of sight of the sight relative         to the longitudinal axis of the sight, the adjusting being         effected by a predetermined angle as a function of the data; and     -   second means for adjusting the longitudinal axis of the sight         relative to a bore axis of the barrel.

The object underlying the invention is, thus, entirely solved.

By the combination of a high-resolution adjustment of the line of sight, preferably in an optical/electronic manner, and, hence, fast, with a precise and, preferably, mechanical adjustment of the sight relative to the barrel, it becomes possible to adjust a range of quadrant elevation angles or lead angles, respectively, such that the firearm may be used efficiently under highly different combat situations.

According to a first preferred embodiment of the invention, the first means adjust a reticle of the sight.

This measure, known per se, has the advantage that a simple and well-tested adjustment of the line of sight with a high angular resolution becomes possible. However, due to the limited field of vision of the optical sighting means this is only possible within a limited angular range.

According to another embodiment of the invention, the second means effect a swivelling at least of optical components of the sight relative to the barrel.

According to a further improvement of this embodiment, the second means effect a swivelling of the sight as a whole relative to the barrel.

These measures have the advantage that a high angular resolution may be guaranteed over a wide range of attack angles.

According to another embodiment of the invention, the second means effect a swivelling movement in predetermined angular steps.

This measure has the advantage that certain course adjustments may be made or may be predetermined which, for example, are based on practical experience. For a particular combat situation in which, for example, a certain elevation of the terrain does not change during the combat actions, this may be compensated by a corresponding angular step and, thereupon, the further operation may be effected by fully setting the line of sight.

In this context it is particularly preferred when the line of sight is adapted to be adjusted within a predetermined range, wherein, when the longitudinal axis of the sight is swivelled by an angular step from a first angular position to a second angular position, the predetermined range in the first angular position spatially overlaps the predetermined range in the second angular position.

This measure has the advantage that a switching hysteresis is generated in which the line of sight, even after the switching by an angular step, is within its adjustment range and not at a limit thereof.

In the context of the present invention it is particularly preferred when during aiming the line of sight, the second means effect a course adjustment and, thereafter, the first means effect a fine adjustment.

This measure has the advantage already indicated above that a preferably mechanical adjustment of the sight relative to the barrel constitutes a basic setting, starting from which the line of sight is adjusted in smaller ranges for a precise and high resolution sighting and, as the case may be, also follows a target object.

A particularly advantageous effect is achieved when during aiming the line of sight the second means effect a course adjustment and, thereafter, the first means effect a fine adjustment and, when during the fine adjustment a predetermined adjustment threshold value is reached, the second means cause the first means to effect another angular step.

This measure has the advantage that the sighting may be effected automatically over several angular steps or course ranges, respectively.

In the context of the present invention, the first means and the second means, preferably, effect an adjustment within a vertical plane. However, in certain embodiments one may also provide additionally, or as an alternative, an adjustment within a horizontal plane.

In embodiments of the invention, the data comprise a distance between a target object and the firearm and/or an elevation of the line of sight between a target object and the firearm and/or a velocity of a target object relative to the firearm.

These measures have the advantage, known per se from prior art fire control installations, that various physical parameters and, as the case may be, also other than the afore-mentioned parameters, which influence the trajectory of the projectile, may be taken into account in order to improve the probability of a proper hit.

It has already been mentioned that, preferably, the first means are configured optical and/or electronic, and that the second means are essentially configured mechanical.

Further advantages will become apparent from the description and the enclosed drawing.

It goes without saying that the features mentioned before and those that will be explained hereinafter, may not only be used in the particularly given combination, but also in other combinations, or alone, without leaving the scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are shown in the drawing and will be explained in further detail throughout the subsequent description.

FIG. 1 shows an extremely schematic combat situation for explaining an embodiment of a firearm according to the present invention;

FIG. 2 on an enlarged scale shows a schematic partial side-elevational view of an embodiment of a firearm according to the present invention, in a first operational condition;

FIG. 3 is an illustration, similar to that of FIG. 2, however, for a second operational condition;

FIG. 4 is an illustration, similar to that of FIG. 2, however, for a third operational condition; and

FIG. 5 is an illustration, similar to that of FIG. 2, however, for a fourth operational condition.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1, reference numeral 10 designates a combat situation within an inclined terrain 12. A target object 14, for example a vehicle, is located at a higher position. A firearm 16, for example a grenade launcher, is located within terrain 12 at a relatively lower position.

According to FIGS. 1 to 5, firearm 16 is provided with a barrel 18 having a longitudinal or bore axis 20. Barrel 18 is provided to launch low velocity projectiles, in particular grenades, having a large diameter of, for example, 30 to 150 mm. Due to the lower muzzle velocity of, for example, 50 to 200 m/s, the trajectory of these projectiles is substantially curved, for example like a parabola.

A sight 26 is mounted on barrel 18 via a joint 22. Sight 26, for example, is a sight telescope. Sight 26 has a high resolution and, therefore, only covers an angular range that is smaller as would be required in the particular combat situation 10.

Sight 26 is part of a fire control system 24. Fire control system 24 also comprises a fire control computer 28 which, in the embodiment shown, is attached to firearm 16 or is integrated into same. However, it may also be configured as a separate unit and may be worn by the gunner, separate from firearm 16.

As shown in FIG. 2, the fire control computer 28 is provided with sensors 30 and 32. Sensors 30 and 32 are to be understood as an example only because in the context of the present invention also systems may be used having only one or more than two sensors. First sensor 30, for example, is a range finder, in particular a laser range finder which senses the distance between target object 14 and firearm 16, as designated by d in FIG. 1. Second sensor 32, for example, is an angular sensor sensing the elevation angle φ of a line of sight 44. Further sensors may sense a velocity v of target object 14, for example a driving velocity of a vehicle or, further, the direction and the velocity of a wind, the ambient temperature, or other parameters that influence the trajectory of the projectile.

The data of sensors 30 and 32 are fed to an evaluating electronic unit of fire control system 24. From these data, the evaluation electronic unit generates control signals for, for example, a quadrant elevation α or a lead angle of firearm 16.

As shown in FIG. 2, sight 26 comprises a reticle 40 as well as an optical element, for example an aperture stop 42, these two elements defining a line of sight 44. The gunner is indicated on the right hand side of FIG. 2 at 46. In the operational condition of FIG. 2, longitudinal axis 48 of sight 46 coincides with line of sight 44, as will be explained further below.

Due to the given elevation angle φ, firearm 16 in FIG. 1 must fire “uphill” because target object 44 is located above firearm 16. Due to that and, further, due to distance d, a quadrant elevation a must be set so that the projectile hits target object 14 on its parabolic trajectory 50. This is achieved in the following manner:

Within FIGS. 2 to 5, it is assumed, for the sake of simplicity, that firearm 16, in contrast to the illustration of FIG. 1, is located within a plane terrain. The elevation angle φ, therefore, is zero. However, the illustration holds true in an abstract consideration, also for the situation of FIG. 1, if one considers line of sight 44 to extend horizontally, independent from its actual inclination.

Moreover, it is assumed that target object 14 is stationary.

FIG. 2 shows an operational condition in which target object 14 is very close to firearm 16, i.e. distance d is very small. Then line of sight 44 and longitudinal axis 48 of sight 26 coincide and extend parallel to bore axis 20. The curvature of the trajectory at such a small distance d is negligible. Reticle 40 is in its basic position.

FIG. 3 shows a second operational condition, in which target object 14 is at a larger distance from firearm 16, as compared to FIG. 2, however, within a still limited distance. In FIG. 3 those elements that are shifted in comparison to FIG. 2, are designated by the same reference numeral, however, by adding an “a”.

At this distance d, the parabolic shape of trajectory 50 has to be taken into account. However, it is sufficient to only activate first means which effect a displacement of reticle 40 with high resolution upwardly, namely from 40 in FIG. 2 to 40 a in FIG. 3. The first means, insofar, are, preferably, electronic or optic and, hence, allow a fast displacement of reticle 40. Such first means are well known to a person of ordinary skill in the art of firearms.

Line of sight 44 remains unchanged because gunner 46 sights target object 14 in an unaltered direction. However, due to the considerably larger distance d and due to the displacement of reticle 40 to 40 a, sight 26 is erected 26 a by an attack angle ν of, for example, 7°. Due to the rigid connection to barrel 18, barrel 18 is taken along, i.e. also erected to 18 a, such that likewise bore axis 20 is erected to 20 a. The quadrant elevation angle α, therefore, is equal to the attack angle ν of 7°.

If, for example, the system allows a maximum attack angle ν of 8°, a quadrant elevation a range of 0°<α<+8° may be created.

FIG. 4 shows a third operational condition in which target object 14 is now located at a substantially larger distance d from firearm 16. Those elements that have been shifted in FIG. 4 relative to the illustration of FIG. 3 are again referred to by the same reference numeral, however, with the addition of a “b”.

In this operational condition, the above-specified range for the quadrant elevation angle α is exceeded. The compensation discussed above in connection with FIG. 3, and being effected by displacing reticle 40, is, therefore, no more sufficient. Instead, through second, preferably mechanical means, joint 22 is adjusted to 22 b, whereby barrel 18 is swivelled relative to sight 26 by an angle, preferably by a predetermined angular step κ of, for example, 13°. This switching-over from the first to the second means may be effected automatically, when the evaluation electronic unit senses that attack angle ν exceeds a predetermined threshold value, for example those 8° mentioned above.

It goes without saying that the angle or the angular step κ, respectively, may not only be adjusted according to the illustration by swivelling the entire sight 26. Instead, it may also be adjusted by, preferably, mechanically adjusting optical components within the sight.

In the illustration of FIG. 4, reticle 40 b is again in its initial position in that operational condition. As a consequence, line of sight 44 b again coincides with the longitudinal axis 48 b. Quadrant elevation angle α is equal to angular step κ and, hence, equal to 13°. During the above-mentioned automatic switching-over between the first and the second means, one may select angular steps κ and threshold values for attack angle ν, i.e., the range thereof, such that the ranges of attack angle ν during a switching-over by an angular step κ spatially overlap.

FIG. 5, finally, shows a fourth operational condition in which target object 14, as compared to FIG. 4, is in a still somewhat larger distance d from firearm 16. In FIG. 5, those elements that have been displaced compared to FIG. 4, are designated by like reference numerals and by the addition of a “c”.

Starting from the course adjustment of FIG. 4, a fine adjustment is now effected in this operational condition by displacing reticle from 40 b to 40 c, corresponding to an erection of longitudinal axis 48 c, relative to an unaltered horizontally extending line of sight 44 c by the attack angle ν of, for example, 7°.

Seen as a whole, in the operational condition of FIG. 5 a quadrant elevation angle α results being equal to the sum of attack angle ν and angular step κ. As a consequence, quadrant elevation angle α=13°+7°=20°. The total range for quadrant elevation angle α, again assuming that the maximum attack angle be 8°, is (13°−8°)<α<(13°+8°), i.e. 5°<α<21°.

In a corresponding manner, elevation angle φ may likewise be taken into account, which has not been done up to now. In a similar manner, further parameters may be taken into account, for example the velocity v of a moving target object 14, by setting a corresponding lead angle, as is known per se.

Further, it goes without saying that the adjustment may not only be effected in a vertical plane, as described above, but may likewise be effected within a horizontal plane. 

1. A firearm for low velocity projectiles having a barrel for launching said projectiles, and a fire control system, said fire control system comprising: a sight having a longitudinal axis; sensors for sensing data of a target object; first means for adjusting a line of sight of said sight relative to said longitudinal axis of said sight, said adjusting being effected by a predetermined angle as a function of said data; and second means for adjusting said longitudinal axis of said sight relative to a bore axis of said barrel.
 2. The firearm of claim 1, wherein said first means adjust a reticle of said sight.
 3. The firearm of claim 1, wherein said second means effect a swivelling at least of optical components of said sight relative to said barrel.
 4. The firearm of claim 3, wherein said second means effect a swivelling of said sight as a whole relative to said barrel.
 5. The firearm of claim 3, wherein said second means effect a swivelling movement in predetermined angular steps.
 6. The firearm of claim 5, wherein said line of sight is adapted to be adjusted within a predetermined range, wherein, when said longitudinal axis of said sight is swivelled by an angular step from a first angular position to a second angular position, said predetermined range in said first angular position spatially overlaps said predetermined range in said second angular position.
 7. The firearm of claim 1, wherein during aiming said line of sight, said second means effect a course adjustment and, thereafter said first means effect a fine adjustment.
 8. The firearm of claim 6, wherein during aiming said line of sight, said second means effect a course adjustment and, thereafter said first means effect a fine adjustment and, when during said fine adjustment a predetermined adjustment threshold value is reached, said second means cause said first means to effect another angular step.
 9. The firearm of claim 1, wherein said first means and said second means effect an adjustment within a vertical plane.
 10. The firearm of claim 1, wherein said first means and said second means effect an adjustment within a horizontal plane.
 11. The firearm of claim 1, wherein said data comprise a distance between a target object and said firearm.
 12. The firearm of claim 1, wherein said data comprise an elevation of said line of sight between a target object and said firearm.
 13. The firearm of claim 1, wherein said data comprise a velocity of a target object relative to said firearm.
 14. The firearm of claim 1, wherein said first means are configured optical.
 15. The firearm of claim 1, wherein said first means are configured electronical.
 16. The firearm of claim 1, wherein said second means are configured essentially mechanical. 